ORDINAL TVI'KS OF MOLARS: IXSKCTIVORA 



19 



ms. pa. 

 me. \ 



mis. pa- 



nic. 



mts. me. pa. 



pr. 



FIG. 68. Molars of tritubercular Insectivores : A, "Chrysochloris," ///-right; B. Potamormle, in' 2 

 right (after Allman, Tmns. Zoo!. Hoc. , ISiitj, pp. 1 - t seq.) ; Centetes sp. (All enlarged.) According to 

 Gidley the outer cusps marked ps, jm, mt , itx, are stylar cusps, the cusp marked /// is really the 

 paracone or paracone + metacone while the ledge-like internal projection marked //// in A and 

 indicated by the anterior basal upgrowth in C is the so-called protocone, the pusterior IKISM! 

 upgrowth being the hypocone ; in B the cusps marked pi, iiil are almost certainly the para- and 

 metacones respectively. See Addendum. IP. 225. 



PS. 



mts. 



pa. ins. 



pa. 



ps. 



pa. me. 



>lts. 



pi-. 



pr. 



ins 1 



mts. 



nits. 



ps. 



nits. 



Fie. ti'.i. Possible but uncertain homologies (according to the tritubercular theory) of the true 

 molar cusps in Zalambdodont (A-E) and Dilambdodont (/'-//) Insectivora, and Cheiroptera (/). 

 A. Centetes; B. Ictops thoumfini (after Matthew). C. "Chrysochloris"; D. Solenodon (after Dnl^son), 

 lSsS'2. E. PotiniiO'jule (after Allman). F. .l/.i/"""'' ; G.Galeopithcct'x; H. Proscnlops (after Matthew). 

 /. Suctinomus brasiliemis, a bat (after H. Allen, IM'H). P'or another interpretation of the cusps in 

 A see the text. In E especially the homologies of the cusps are very uncertain. 



Postscript. December, 1006. An apparent solution of this puzzling problem is given on 

 page 225. 



The abbreviations in Figs. 68, 69 are incorrect and should be disregarded. The 

 true interpretations are given in the text. 



